PROCEDURE AND APPARATUS FOR PRODUCING ENERGY FROM TEMPERATURE DIFFERENCE OF OPEN AIR AND WATER

Abstract: Solar and wind energy are still costly. Their yield is poor at times when energy is needed most, that is, in winter in Europe. The invention relates to a method and an apparatus for producing electricity by means of vertical wind and/or horizontal wind provided by temperature difference of open air and water. In the winter, the water temperature is above zero (in centigrades). The condensation heat of power plants is about +15 CEL. In freezing weather (temperature below zero), the temperature difference of water and air is at the discharge site of condensation water up to 40 CEL. A chimney (4) resembling a condensation tower draws open air (3) heated in a heat transfer means (5) upwards. The direction of the flow is deflected with vanes (6), whereby the power plant, or the heat transfer means only, rotates supported by a pontoon (2). The heat transfer means (5) is a siphon. Air is removed from the pipes of the transfer means with a low pressure compressor. The pipes are filled with water by air pressure. The flow is maintained with the aid of forces generated by the rotation. The vertical chimney comprises vanes appropriate for recovering horizontal wind, or the vanes are connected to the sides of the chimney like sails. The apparatus is a vertical axis windmill, bearably carried in the water part of the time.

Description: PROCEDURE AND APPARATUS FOR PRODUCING ENERGY FROM TEMPERATURE DIFFERENCE OF OPEN AIR AND WATER. The present invention relates to a method and an apparatus for use as an electricity producing means typically rotating on the surface of the water and utilizing tempera¬ ture difference of water and air, and horizontal wind. The invention particularly relates to the method according to preamble of claim 1 and to an apparatus according to preamble of claim 5. In the method, one and same apparatus recovers electricity both from upward directed flow of open air heated with water and from wind, whereby the means operates as a windmill with vertical axis. Use of heat for producing vertical flow is known in the form of vertical wind power plant. A power plant recovering horizon¬ tal wind and vertical wind is below called a combined wind power plant. The power plant or a part thereof is rotating on the surface of the water supported by a pontoon. With the pontoon a bearing system is simultaneously provided which is appropriate for both a vertical and a horizontal wind power plant. Recovering electricity from rotary movement is known in the art. It is advantageous to heat open air with water using a heat transfer means based on siphonage. Here, the air pressure raises the water up to the height of ten meters at most in the tubing. The water flow in the pipes of the heat transfer means is provided by utilizing the rotary movement. In the present method, a heat transfer means disclosed in the utility model U930372 may also be used, in which air first is first conveyed under the water surface, e.g. within a pontoon. The present method is essential when trying to produce electricity at low cost from wind and/or vertical wind. The great volume of air needed in a vertical wind power plant is heated advantageously with a transfer means according to the present method. The rising of hot air upwards is known in the art also as a chimney effect. A stationary vertical power plant has been built at least in Spain. The great volume of heat to be needed is generated with the aid of a light transmitting cover when the sun is heating the earth and the earth in turn the air. The cost of the cover is up to 70% of the price of the power plant. There should be a great quantity of cover because the power achieved from the sun is small, the maximum being 1 kW/m 2 . Even in the best areas the average is only about 200 W/m 2 . However, with the method electricity has been reported to be achieved at low cost (60 Finnish pennies per kWh). A great number of patent applications concerning vertical wind power plants and additional features associated therewith are available, such as the following: US 4 275 309, US 3 936 652, GB 2 081 390, GB 2 055 980, DE 3 107 252, DE 3 006 702, DE 402 647. An equivalent technology is used in fixed condensation towers of power plants. A typical height therein is 150 m. Fully commercial technology is used in windmills, both in those with horizontal and vertical shafts. In the application SF 790 746 a windmill with a vertical shaft is well disclosed. The method of the present invention is mainly characterized in what is presented in the characteristic features' part of claim 1, and the apparatus of the invention is mainly characterized in what is presented in the characteristic features' part of claim 5. Energy saving is of greatest importance when the energy consumption is highest. At such times there is, unfortunately, hardly any sunshine nor enough high winds in Finland. The properties of air as a circulating agent in a thermal energy machine in cold circumstances are advantageous by one third than in hot circumstances. The present method acts best in freezingly cold weather. In great water masses, such as in seas, lakes and rivers, there are almost unlimited quantities of energy stored to heat very cold air, i.e. in weather when the tempera¬ ture is below the freezing point. In industrial countries also condensation heat and other waste heat is formed in electricity production. With the temperature difference (40 CEL) of condensation water (15 CEL) and freezing air (-25 CEL) the air is heated over 30 CEL. In a Spanish pilot power plant the air was heated with the sun by about 20 CEL. Also the natural water is always at a temperature of few degrees above the freezing point. The freezing air can thus be heated with water almost unlimitedly to serve as the source of energy in vertical wind power plants. The contents of the present invention, that is, a combined wind power plant is a novel method of electricity production in which renewable energies can be utilized more advantageously than before. The greatest power from the vertical wind is derived when the energy need is greatest, that is, in freezing cold weather. The same apparatus is enabled to utilize horizontal wind when the wind is blowing. The power plant can be bearably carried in the water. The invention also includes a heat transfer means for transferring a great quantity of thermal power from the water into the air advantageously and reliably. The requisite thermal power required in a vertical wind power plant is of the order 1000 MW. Raising water into the pipes can advantageously be accomplished by siphonage so that the potential energy of the water remains there and will not be lost. The flow in the water pipes is maintained by the forces generated by the rotation of the apparatus and by increased density of the cooling water. The rotary movement is produced using simple vanes at good aerodynamic effi¬ ciency. 80% efficiency is typically achieved using a centrifugal blower. In windmills rotating freely in the wind, the efficiency is probably below 50%. This difference can be explained by the envelope of the blower. Since the entire apparatus is rotating in the water, no separate wind turbine is necessarily needed. The electricity is recovered by retarding the rotation with the generators. A preferred procedure to produce electricity from temperature difference of water/open air and/or wind is to use the present method and an apparatus like one defined in the characteristic features' part of the protective claim. The most important advantages of the invention are as follows: — no high cost recovering means is needed in the method. — power is produced by the method 24 hrs on cold days at temperatures below 0°C. — the temperature difference is available almost unlimitedly in cold countries when the consumption is greatest. — the heat transfer means according to the invention efficiently transfers great quantities of heat. — the rotation inhibits potential problems caused otherwise by freezing and refuse accumulation. — with the same apparatus also the horizontal wind is recovered. — the power plant, or part thereof, is rotating so that electricity can be recovered without wind turbines. — with the method, electricity can be generated also from heat stores in tropical seas, particularly at night times. Preferred locations are discharge locations of waste and condensation heat, such as nuclear power plants, and as cold shores of open seas as possible. The output of vertical wind is in proportion to the surface area (d A 2) of the vertical chimney of the power plant. The output is also in proportion to height power 1.5 (h Λ 3/2). The delivery price is in proportion to the surface area (d*h) of the envel¬ ope. An optimal power plant would be as large in size as possible because the output increases more steeply than the structures of the envelope. A limitation thereto is caused by siphonage. The greatest height of the heat transfer means, and consequently, of the air inlet, from the water surface is below ten metres. The optimal flow rate is dependent on the height of the tower. The efficiency is proportional to the height divided by the outside temperature and specific heat. The thermodynamic efficiency, that is, the electricity obtained divided by the consumed heat, is merely a few per cents. The heat is required to be free. The "efficiency" of ordinary wind is even poorer. The invention is described below in detail, reference being made to the accompany¬ ing drawings. Fig. 1 presents according to the invention a vertical wind power plant rotating in the water in elevational view, partly sectioned. Fig. 2 presents part of a pontoon of a vertical wind power plant floating in the water and of a heat transfer means in elevational view according to the invention, the structure being partly sectioned. Fig. 3 presents a simple combined wind power plant floating in the water according to the invention, in top view and in a position utilizing horizontal wind. Fig. 4 presents a combined power plant according to the invention in elevational view. The horizontal wind is being recovered continuously by means of sail-like vanes. A vertical wind power plant, as shown in Fig. 1, rotates in the water 1 supported by an annular pontoon 2. Open air 3 is drawn in through the lower part of the power plant and it exits up through a high air chimney section 4. The chimney has been so shaped that very little pressure is consumed in flow resistances. The speed in the lower section becomes gradually accelerated and in the upper part, the expanded section converts the speed back into static pressure. The air passed through the heat transfer means 5 nearly reaches the temperature of the water. The suction is provided by the chimney effect. The heated air tends to rise up while being lighter than the environment. The vanes 6 on top of the pontoon deflect the direction of the air current, thus causing the power plant to rotate. The same principles concern the designing of vanes as designing blower vanes. It may be useful to employ, e.g. lead vanes in front of the blower vanes rotating together with the pontoon (FI 790746). The rotation can be utilized both in electricity production and in heat transferring. Electricity can be generated with generators 7 which at the same time maintain the construction in place. This location of the generators is advantageous as regards maintenance. On top of the air inlet, a roof 8 could be provided to prevent snow from getting into the heat transfer means. Fig. 2 shows how a heat transfer means 5 comprises water pipes 10 and thermally conductive fins 9 in association therewith. Because of air pressure, the water rises into a manifold 11 through a rise pipe in the middle when air is removed from the tube system at point 12. The flowing of the water is generated by forces caused by the rotation of the pontoon or of the entire construction. One of such forces is centrifugal force, which in the pipe 11 of the figure induces flowing from the middle towards the heat transfer means. The flow is also produced without using the rise pipe 16 in the middle, by directing the water-raising pipe upstream and the discharge pipe downstream at 13. The flow rate of the water is dimensioned by selecting the magnitude of the flow losses of the pipe and the speed of rotation of the heat transfer means as desired. Also the flow produced by centrifugal force is intensified by directing the pipe returning from the heat transfer means downstream as at point 13. Cooling of the water in the heat transfer means 5 also increases the flow because the cool water weighs more than warm. Heat transfer can be intensified by conducting the air through water jets 14 in which heat is efficiently transferred from the water into the air. When using water jets, the siphonage idea is not operational, but the potential energy of the water becomes lost. When small temperature differences are in question, the loss can be tens of percen¬ tages of the electricity obtained. Electricity can be recovered from the rotary movement also at point 5 where the stationary rise pipe 16 has been bearably carried to the rotating construction. The rise pipe 16 remains in place when anchored to the bottom with rods 17 through which, for instance, supply of electricity into the network can be arranged. External sites for generators at which energy may also be recovered and the anchor¬ ing carried out, are indicated by numeral 18. In the proximity of point 18, a stationary construction may in such instance be needed. The rotary movement and the water returning from the heat transfer means at point 13 makes the water flow away from the power plant. At the same time, the freezing tendency is reduced when the flow brings new water for cooling from below the transfer means. Potential loss or condensation heat is conducted under the power plant or directly into the rise pipe 16. In practice, e.g. the condensation pipe and the rise pipe of a nuclear power plant cannot be connected. The condensation water needs to be discharged also during maintenance of the vertical wind power plant. Fig. 3 presents in simplified manner how a chimney needed in a vertical wind power plant can be produced from the vanes 19 of the vertical axis windmill, which alternatively serve as a chimney and as a vane of the windmill. The vanes may be enabled to move supported to the roof 8 and to the heat transfer means thereunder. The generator is indicated by numeral 7. In heavy storms the vanes are withdrawn into chimney position to prevent the apparatus from being broken by excessive wind force. As shown in Fig. 4, the vane may also resemble a sail. When the chimney 4 is fixed, a sail-shaped vane 20 may be opened from the side thereof in the downwind section. The design is particularly useful in a slowly rotating power plant, whereby the wind can be significantly retarded with the sail. The appliance is typically 150 m high. Let the appliance be dimensioned for 25 CEL air temperature rise (-23 CEL > +2 CEL). This can be achieved without any condensation heat. The suction of the chimney is 200 Pa (density change * gravity constant * height). Let the dimensioning air current be 30000 m3/s (100 MW). The diameter must be over 100 m so that the speed and pressure loss remain moderate in the air inlet and outlet. The height of the inlet is restricted to less than 10 m on the water surface because of the siphonage. Air circulation may also be used inside the pontoon under the water surface. The power potential is 6 MW (30000 m3/s*200 Pa). Let us be pessimistic and reserve half (50%) for losses, whereby the net electrical power is 3 MW. On the Finnish coast the stability of the peak power is about 4500 h/year, thus, the vertical wind power plant of the example will generate 13500 MWh energy a year. The value of the energy is, at Finnish price of electricity, 20 Finnish pennies per kWh, is 2.7 million FIM per year. The energy obtained from the horizontal wind is of significance particularly when there is no temperature difference, that is in the summer. The annual yield with the horizontal wind is clearly less than with vertical wind. The power loss caused by the rotation of the pontoon can be estimated by the aid of pipe flow. Let us think that the pontoon is a pipe, the quantity of water contained wherein weighs as much as the structures on the water. In a typical installation (h=150 m) the overall weight is of the order 2000 tn. An envisioned pipe would be 2 m in diameter. From the pipe flow curves, 0.02 kPa/m friction loss is obtained for the internal 3 m/s pipe flow. The overall length of the pontoon is 450 m, so that the entire rotation loss is about 10 kW (length * friction loss). The loss is below one per cent of the output. The small loss is explained by the fact that no water is displaced by the pontoon. At 3 m/s circumferential pontoon speed a dynamic pressure of about 10 kPa can be produced. The pressure caused by the centrifugal force is lower than that. 50 Pa/m pressure is needed for pumping, when based on experience, thus totalling in 1.2 kPa(50 Pa/m * 24 m) for one siphon loop (= from the surface 8 m high + 8 m to the side and back into water). In a typical installation (h = 150 m), the total water flow is 30 m3/s. The pumping rate is 36 kW (1.2 kPa * 30 m3/s). This means more than one per cent loss in the power. It is obvious to a person skilled in the art that the number of vanes 6,19,20 and water pipes 10,11,16 per location, and the shape of the tower or pontoon may vary. In special instances the vanes can be bearably carried, e.g. with a rail. The chimney can be built to be fixed and the heat transfer means may be allowed to rotate in the water. Temporarily, high ratings may be produced by burning any kind of fuel within the power plant. The invention is not confined to the examples of the figures and it may vary within the scope of the claims below.

Claims: Claims 1. A method for producing energy with vertical wind and/or horizontal wind provided from temperature difference of open air (3) and water (1), in which method a heat transfer means (5) and/or the entire power plant are rotating supported by a pontoon (2) on the surface of the water, characterized in that the rotation is provided with vanes (6 and/or 19;20) from air flow sustained by chimney effect to the heated air of a vertical chimney (4) and the force of wind affecting the vanes (6 and/or 19;20). 2. Method according to claim 1, characterized in that in the method the horizontal wind force is intensified with vanes (19) forming a vertical chimney (4) or with sail- resembling vanes (20) attached on a side of the vertical chimney (4). 3. Method according to claim 1 or 2, characterized in that in the method the vertical chimney rotates supported by the water acting as a bearing means and that the rotary movement is transformed partly into electricity by retarding the rotation with generators (7) and partly into pumping energy of the water circulating in the heat transfer means (15). 4. Method according to any one of claims 1 to 3, characterized in that the rotation is achieved with vanes (6) in association with the heat transfer means (5). 5. An apparatus for producing energy with vertical wind and /or horizontal wind produced from temperature difference of open air (3) and water (1), the heat transfer means (5) of which apparatus and/or the entire apparatus have been placed so as to be rotating supported by a pontoon (2) on the surface of the water, characterized in that the apparatus comprises a vertical chimney (4) and vanes (6) thereinside, and at least one such vane structure (6 and/or 19; 20), by means of which said rotation on the water surface has been adapted to be provided. 6. Apparatus according to claim 5, characterized in that the vertical chimney (4) has been comprised of vanes (19) or on a side of the vertical chimney (4), sail- resembling vanes (20) have been attached for intensifying the horizontal wind power and that the water forms a bearing means for the rotation of the apparatus. 7. Apparatus according to claim 5 or 6, characterized in that the apparatus is provided with a generator/generators (7) for changing the rotary movement partly into electricity by retarding the rotation and partly into pumping energy of the water circulating in the heat transfer means (5), and that the water forms a bearing means for the rotation of the apparatus. 8. Apparatus according to any one of claims 5 to 7, characterized in that the vanes (6) of the apparatus have been connected to the heat transfer means (5). 9. A heat transfer means used in association with the method according to any one of claims 1 to 4 and/or of an apparatus according to any one of claims 5 to 8, for heating open air with water, comprising flow pipes (10,11,16) and powerful heat transfer parts (5), the water flowing thereinside heating the air (3) flowing on the outer surface of selfsame parts, characterized in that the raising of the water above the surface is accomplished by the aid of syphonage, and the flow in the water pipes is provided by centrifugal force caused by the rotation and/or speed of the pontoon relative to the water.

Inventors: HEINOLA REINO, LAIHO AARO, HEINOLA, REINO, LAIHO, AARO
Applicants: HEINOLA REINO, INSINOEOERITOIMISTO AARO LAIHO, LAEMPOETAITO OY, LAIHO AARO, HEINOLA, REINO, INSINOEOERITOIMISTO AARO LAIHO OY, LAIHO, AARO
Application year: 1994
Main classification: F03D9
IPC codes: F03D1